Process for treating coal and like substances



' l types, .but

- Patented Jan. 20, 1931 UNITED: STATES PATENT OFFICE WILHELM HECKEL', Q1 HAMIBORN, GERMANY, ASSIGNOR, BY MESNE ASSIGI N'I ENTS, '10

' C(H. ELLSWORTH PBQCESS FOR TREATING COAL AND LIKE SUBSTANCES No Drawing.

My invention relates'to the treatment of 10 peratures employed hitherto in the" treatment of coal, and the like for the production of gas for industrial uses are destructive of certain hydrocarbons, particularly methane and heavy liquid hydrocarbons, which become decomposed or polymerized at-such high temperatures. I have further ascertained that by restricting the heat to which the gas will be subjected at any stage after evolution from the coal or other bitumen-bearing substance to a relatively low temperature (for instance about 500 0.), such objectionable decomposition or polymerization is avoided, the heavy hydrocarbons are obtained in their original condition instead of becoming wholly verted 'into coke-oven tar, and additional advantages are secured with respect to the solid and to the non-condensable" gaseous products (i. e. gaseous products'non-condensable at atmospherietemperature, as one which also result from the treatment. The hea hydrocarbons, particularly'of the aliphatic series, and light oils of the aliphatic seriesQwhich my'treatment yields, have valuable properties as lubricants.

Briefly stated, my invention consists in subjecting the bitumen-bearing substances to a temperature not exceeding a maximum.

of about 5009 (1., that is to say, a temperature below the decomposition and polymerization oint of the hydrocarbons originally evolved om such substances. The treatment may be carried out while the material is stationary orpractically so, for instance, in upright 'retorts or furnaces of well known referably the. material is kept uring the heating, and-rotary kilns of certain existing'types" are available in motion so for this purpose. Inasmuch as usual apparaor largely con skilled in the art will readily understand) Application filed August 30, 1921. Serial No. 496,973.

tus may be employed for my process, I have deemed it unnecessaryto furnish a drawing of such apparatus. The treatment may be carried out continuously or intermittently. The result of the treatment is the production of a solid, a type of coke (low-temperature coke) which has considerable heating 7 value and which may be utilized for any'of the purposes for which coke is adapted, such as heating, the making-of producer gas or of water gas, etc. 'Another part of the products is obtained (after condensation) in liquid form, this portion being a mixture of tar, oils and pitch. This liquid or condensable portion (1. e. the portion condensable at or .above atmospheric temperatures, as one skilled in the art will readilyunderstand) is rich in hydrocarbons of the aliphatic series (i. e. in members of the broad group of liquid hydrocarbons), also in oils of the aliphatic series (i. e. in liquid hydrocarbons, particularly in those havin lubricating properties), but free from nap thalene, and the pitch residue is poor in hydrocarbons (i. e. the

pitch is relatively devoid of free hydrocarbons per se or, in other words, hydrocarbons in a non-polymerized or fixed state are not present in the. pitch). As the material is being heated, the bituminous matter con tained" thereinis melted, the liquid hydrocarbons contained in the material are vapotized, while the hydrocarbons contained in the material as gases are liberated in that form. The-condensable vapors (i. e. the portion condensable at or above atmospheric temperatures, as one skilled in the art will readily understand) are treated in any suitable manner (as by a well known cooling operation, preferably in successive stages with a separation of some products at the end of each stage) to obtain thereirom the liquid products desired,

.The gaseous "portion oi the products articularly the' tar, the aliphatic lhydrocar ons and the. aliphaticmay receive the usual cleaning or series, but contains very little hydrogen, or even none at all.. The gas obtained, therefore, is of considerable heating value, being far superior in this respect to ordinary producer gas. v

. My process, therefore, yields three products or classes of products, viz; first, a solid or substantially solid residue which I term low-tem erature coke; second,ta mixture of a specia tar (low-temperature tar), heavy hy rocarbons and. oils, which have valuable lubricating properties; third, a gas of high heating value.

a The temperature of the gases or other medium employed for heating the bitumenbearing substances may be considerably above 500 C. for instance 900 C.), but

.it is important that these substances themselves should not reach a temperature above the decom of the hy rocarbons orlginally contained in said substances. 7 Only low-temperature tar, that is to say, tar produced at temperatures not exceeding a maximum of about 500 G. contains the hydrocarbons in the same chemical condition. in which they occur in the coal or other bitumen-bearing substance (i. e.

the chemical structure of the hydrocarbons are substantially'unchanged by the low temperature heat treatment or, in other words, compounds in the form of'aliphatic compounds in-the coal would not be. converted n ring compounds by distillation and vice versa), and in whichsuch hydrocarbons have specific useful properties similar to those of petroleum and its products. If the tar- ,containing gases are subjected to materially portion of low temperature tar, C. in

the second stage to cause condensation of another portion of low temperature tar, and

35 C. in the third-stage to cause condensation of liquid hydrocarbons including oils of the aliphatic series having lubricating alue and then collecting the volatile products uncon'clensed at 35 C.

In testimony whereof I have hereunto set m hand. y DR. WILHELM HECKEL.

ition 'and polymerization point higher temperatures, the resulting tar will not be the valuable low temperature tar, but a lower grade tar of the same character as coke-oven tar. The gases and vapors which,

at the time of their separation from the solid product, may have a temperature of about 420 C. may be further treated, for instance, by washing and cooling'inthree stages, as to 130 C. in the first stage. to 65 ,0. in the second, and to 35C. in the third, to'separate the tar (by the first two stages) and the oil (by the-third stage).

When in the claim the term coal is used, I

it is intended to include equivalent bitumenbearing substances of a solid nature.

I claim: I

The process of thermally treating coal to produce a plurality of products, including coke, low; temperature tar relatively free from naphthalene, oils of the aliphatic series havin lubricating properties and a gas rich in by rocarbons of the ethylene and paraflin series which comprises subjecting the said substances to a temperature not exceeding approximately 500 C..to cause the distilla- -tion of volatile products, continuin the distillation at a temperature not excee 'ng 500 C. until the substance has received its treat- I 

